体布拉格光栅实现光谱光束合成的极限效率

Ultimate efficiency of spectral beam combining by volume Bragg gratings.

作者信息

Drachenberg Derrek R, Andrusyak Oleksiy, Venus George, Smirnov Vadim, Lumeau Julien, Glebov Leonid B

出版信息

Appl Opt. 2013 Oct 20;52(30):7233-42. doi: 10.1364/AO.52.007233.

DOI:10.1364/AO.52.007233

Abstract

Spectral beam combining (SBC) by volume Bragg gratings (VBGs) recorded in photo-thermo-refractive (PTR) glass is a powerful tool for laser applications that require higher radiance than a single laser unit can achieve. The beam-combining factor (BCF) is introduced as a tool to compare various beam-combining methods and experiments. It describes the change of radiance provided by a beam-combining system but is not affected by the initial beam quality of the combined lasers. A method of optimization of VBGs providing the maximum efficiency of SBC has been described for an arbitrary number of beams. An experiment confirming the proposed modeling for a two-beam SBC system by a single VBG has demonstrated a total combined power of 301 W with a channel separation of 0.25 nm, combining efficiency of 97%, close to diffraction limited divergence with M(2)=1.18, BCF of 0.77, and spectral radiance of 770 TW/(sr·m(2)·nm), the highest to date for SBC.

摘要

通过记录在光热折射（PTR）玻璃中的体布拉格光栅（VBG）实现的光谱光束合成（SBC），是一种用于激光应用的强大工具，适用于那些需要比单个激光单元所能达到的更高辐射度的情况。光束合成因子（BCF）被引入作为比较各种光束合成方法和实验的工具。它描述了光束合成系统所提供的辐射度变化，但不受合成激光的初始光束质量的影响。对于任意数量的光束，已经描述了一种优化VBG以实现SBC最大效率的方法。通过单个VBG对两光束SBC系统进行的实验，证实了所提出的模型，该实验展示了301 W的总合成功率、0.25 nm的通道间隔、97%的合成效率、接近衍射极限的发散度（M² = 1.18）、0.77的BCF以及770 TW/(sr·m²·nm)的光谱辐射度，这是迄今为止SBC的最高值。